Slitting-knife for excelsior-cutting machines.



No. 627,765. Patented lune 27, I899. W. J. D. THOMPSON.

SLITTING KNIFE FOR EXCELSIUR CUTTING MACHINES. I

(Application filed Feb. 9, 1898.)

, knives of the set and holder therefor.

UNITED STATES PATENT OFFICE.

" WILLIAM JOHN 1). THOMPSON, OF TORONTO, CANADA.

SLITTING-KNIFE FOR EXCELSlOR-CUTTING MACHINES SPECIFICATION forming partof Letters Patent N 0. 627,765, dated June 27, 1899'.

Application filed February 9, 1898. Serial No. 669 ,693. N mod l-l To towhom it may concern/.-

Be it known that I, WILLIAM JOHN D. THOMPSON, inventor, of the city ofToronto, in the county of York, in the Province of Ontario, Canada, haveinvented certain new and useful Improvements in slitting-Knives forEXcelsior-Outtin g Machines, of which the following is a specification.

My invention relates to improvements in what are known in the art asslitting knives or spurs for eXcelsior-cutting machines; and the objectof the invention is to devise a form of knife to be used in pluralityand holders therefor, whereby all classes of timber, whether green orwet or not, may be expeditiously slit or scored suitable for excelsiorwith less power and less waste than by the knives heretofore used and inwhich the knives need not be sharpened, but only jointed and set whenworn, and thus effect a saving of time and labor in this respect also;and it consists, essentially, of slitting knives or blades made ofuniform thickness from end to end and held apart by spacing andreinforcing bars of peculiar construction, such knives or blades andbars being held in a suitable slot in a holding-block and constructedand adjusted in the manner hereinafter more particularly explained.

Figure 1 is a perspective view, intermediately broken away, showingportion of the Fig. 2 is a cross-section. Fig. 3 is aplan view showingportion of the knives and ends of the reinforcing-bars. Fig. 4 is an endView showing portion of the knives and reinforcing-bars preferably, of.thin steel of about thirty-gage.

The thickness and size of the knives are exagknives whatever.

gerated in the drawings for the purpose of clearness. The knives B havedouble beveled end edges 1) b, ending at the center in a fiat edge point5. It is to be particularly noted that I do not sharpen the beveled endsof the When the knives are jointed so as to present a series of broadpoints I) flush with each other and are filed so as to present a seriesof double beveled end edges at each side of the broad point, slight burswould be formed on these beveled ends and on the broad point, and theseof course can be-removed by filing in between; but under nocircumstances is it necessary to sharpen the knives. Each blade isseparated from its adjacent blade by a spacing or reinforcing bar, ofsoft metal, C. The bars 0 are provided with V-shaped notches cut fromthe top and bottom corners inwardly, so as to form an apex c. The outerends of the metal of course brace or reinforce the knives B to the veryedge of their beveled ends, leaving the portion b of the knife perfectlyfree for cutting purposes.

' In practice the knives sharpen themselves, and even the burred edge,hereinbefore referred to, may not be taken off,'as within a very shorttime the knives, being so thin, are sufiiciently sharp to perform thiswork very perfectly. The inner ends of the spacingbars are provided withan offset 0 which projects against the edge of the holding-block belowthe slot, and thereby holds the forward ends of the spacing-barsperfectly flush with each other. The notches serve to allow of the stockpassing freely from between the knives, and thus prevent choking, the V-shaped form of the notch serving to a great extent to this end. Theknives and their spacing-bars held between them are securely heldtogether by the end set-screws A A,

which extend through the end of the block A and abut the end of theknives- In order to provide for the adjustment of the knives forwardevenly as they wear and their proper jointing and beveling, I preferablyprovide two screw-spindles D, which are securely held in the block A atthe forward end, and a cross-bar E, with holes 6 in it, through whichthe screw-spindle D extends. I also provide thumb-nuts F, only one ofwhich is shown, on the end of the screw-spindles. By loosening theset-screws A A and turning on the screw-spindles D the bar E will ofcourse push the cutting apexes of the knives all forward evenly.

It has been found in slitting timber that is green with knives having abeveled sharpened cutting edge and located close together, one abuttingthe other, that they would be frequently choked up, thereby seriouslyimpairing their utility and also necessitating setting the wood aside todry in order to successfully slit it. In fact, the knives would becomechoked up even were the wood not green. The power required was Verygreat in this beveled form of abutting knives, as the Wood would becomebridged in between them; but this was not all, as a still greaterobjection was incident to this form of knife-viz., the difliculty andexpense of sharpening a set of them. Ordinarily it took a mechanic fullyhalf a day to sharpen and set the old knives, as they had to becompletely removed from the holder and each sharpened separately.

By my structure all of the knives can be jointed without removing themfrom the holder.

What I claim as my invention is 1. In combination in aslitting device, aplurality of thin knives having their upper and lower front corners cutoff to present beveled ends, the side faces of the knives being flat theentire length of the same, space-blocks interposed between the faces ofthe knives, a

holder for the same having a slot within which the knives fit and areheld in alinement, said holder having upper and lower beveled sidesconverging at the front to the slot at an angle precisely correspondingto the angle of the bevel of the knives as and for the purposespecified.

2. In combination, in a slitting device, a

holder, a plurality of thin knives held thereiii having their upper andlower front corners cut ofi to present beveled ends, the side faces ofsaid knives being flat through the entire length of same, space=blocksinterposed between the faces of the knives and having V- shaped notchescut in the top and bottom corners at a corresponding angle to the anglesof the bevel of the knives whereby the center of the knives opposite theend of the block is supported rigidly and the top and bottom edges ofthe knives at the points of bevel are flexibly supported as and for thepurpose specified.

3. A slitting device for excelsior-cutting machines and the likecomprising a suitable holder and regulating-slot therein, a plurality ofknives set in alinement in the slot and provided with double beveledends, set even and having broad points jointed and the knife of the samethickness from end to end, suitable reinforcing and spacing bars placedbetween the knives from end to end of the set so arranged as to leave aminimum amount of steel at the point of the knife and the reservedlength of the steel of each blade to the rear of the holding-block,substantially as described.

4. A slitting device for excelsior-cutting machines and the likecomprising a suitable holder and longitudinal slot therein, a pluralityof knives set in alinement in the slot and provided with double beveledends set even and having the broad points jointed and the knife of thesame thickness from end to end, and suitable reinforcing and spacingbars placed between the knives from end to end of the set and havingV-shaped notches formed in the upper and lower corners of the bars asand for the purpose specified.

A WILLIAM JOHN D. THOMPSON.

Witnesses:

B. BOYD, A. H. MCADAM.

